Cleanup to remove a “black goo” substance that was discovered this summer in the beach area of Kershaw Park is scheduled to begin Oct. 16, said James Sprague, the Canandaigua public works director.

“The cleanup will consist of excavating contaminated material and shipping it off site for disposal,” City Manager Kay James said in an email. “The excavation will continue until all contaminated material in the swim beach has been removed.”

The beach closed July 18 after an unknown black oily substance was discovered in the area. City officials announced July 26 that the beach would remain closed for the season.

Department of Environmental Conservation (DEC) Regional Spill Engineer Scott Rodabaugh said the cleanup would most likely take four weeks, and the beach should be open in time for Memorial Day.

Rodabaugh added that aqua-dams will be utilized for the cleanup. The dams are portable and made of a hard rubber — they’re six-feet high and 100-feet in length and will be used in four sections for the excavation.

It is still not clear on what exactly the substance is, James said.

“At this point additional work to identify it will only be done as needed to arrange for its disposal,” she said.

During the summer, Kevin Olvany, the Canandaigua Lake Watershed manager, said the substance most likely dates back to the 1920s or early 1930s. It was analyzed by Dr. John Hassett, a professor of chemistry at the SUNY College of Environmental Science and Forestry, he estimated that the substance is most likely old, used crankcase oil from vehicles dating back to the 20s and 30s.

While the extent of the excavation is still unknown, the costs for the clean up will still be divided between the city and the DEC, James said. The DEC is expected to pay for cleaning up the areas that are considered to be contaminated, and the city will be responsible for the cost of cleaning up the areas that are just construction and demolition debris. The city has a Kershaw Park reserve fund with about $90,000 in it. Payment will most likely come from that, James said during the summer.

Originally, the contractor was going to be National Vacuum Corp., but that has changed. The contractor is now Environmental Products & Services of Vermont, Inc., in Syracuse, Sprague said.